Don't close waitOnExit terminals when pressing modifier keys

Fixes #42066

src/vs/workbench/parts/terminal/electron-browser/terminalInstance.ts

@@ -784,6 +784,12 @@ export class TerminalInstance implements ITerminalInstance {
 
 	private _attachPressAnyKeyToCloseListener() {
 		this._processDisposables.push(dom.addDisposableListener(this._xterm.textarea, 'keydown', (event: KeyboardEvent) => {
+			switch (event.key) {
+				case 'Meta':
+				case 'Shift':
+				case 'Alt':
+				case 'Control': return;
+			}
 			this.dispose();
 			event.preventDefault();
 		}));